1. Field of the Invention
This invention relates generally to garments designed to support the abdomen of a pregnant woman and, more particularly to garments designed to support the woman's spine and pelvis.
2. Description of the Related Art
The posterior pelvic joints, also called the sacro-iliac joints, are functional joint complexes that connect the two pelvic bones (innominates) to the wedge-shaped tailbone (sacrum). The movement of the pelvic bones within this functional joint complexes occurs in three planes of motion. The movement within these three planes is referred to as the anterior and posterior rotatory movements of the innominates. Posterior rotatory movements of the pelvic bones increase the stability of the sacro-iliac joints. Conversely, anterior rotatory movements of the pelvic bones reduce the stability of the sacro-iliac joints.
Like the movement of the pelvic bones, the shoulder complex (scapular-humeral complex) is another functional joint complex that involves movement in several planes of motion. The structures in the shoulder involve the clavicle, the scapula, the upper spinal vertebrae, and the upper end of the humerous.
Humans should move in a reciprocal (contra-lateral) manner when walking which means that the left upper limb and right lower limb function as a unit and the right upper limb and left lower limb function as a unit during upright movement activities. Ideally, when walking, the right arm and left leg should swing forward at the same time as does the opposing left arm and right leg, respectively. By using a side-to-side counter-balance between the upper and lower limbs, increase stability is achieved during upright movement activities.
When walking, the moment of highest challenge on these functional units occurs just after the heel of the leading foot strikes the ground and body's weight begins to project over the foot. At this moment, the pelvic bone experiences its greatest stability challenge as the upward projecting force coming through the lower limb is met by the opposing downward projecting force created by the weight of the forward leaning upper body. At the same time, the opposing shoulder complex is at its moment of highest strain as the arm and shoulder are projecting forward to counterbalance the forward step of the opposite lower limb. What is observed over the shoulder complex is a forward and inward movement of the arm, a forward and outward movement of the shoulder blade, and an increased reverse curve in the upper back.
In pregnancy, the additional weight of the fetus in front of the pelvis further challenges these functional units by moving the pelvic joints towards their less stable, anterior rotatory position as well as creating additional compensatory torsional movement through the opposing shoulder complex.
During pregnancy, the position and weight of the fetus and increase size of the uterus disrupts the desired, upright balance of the body. In response to growth of the fetus and uterus, the pelvic bones rotate forward in a three dimensional pattern and the amount of curvature to the spine increases. To maintain an upright balance, the body compensates by swaying the shoulder backwards. The consequence of this postural disruption is a progressive increase in the upper and lower curves of the spine. As a result, lower back and pelvic pain is a major source of discomfort in pregnancy.
The inventors believe that what is needed is a maternity body support that provides greater functional stabilization. In order to provide functional stability, the body support should apply forces to the pelvic bones and shoulder complexes which (a) directly reverse or oppose their direction of maternity induced stress in all planes of motion, and (b) provide direct vertical support. Also, the garment should apply forces to the shoulder complexes which reverse or oppose the compensatory movements. In other words, the directional force applied to the front side of the pelvic bones needs to be: (a) backward, upward and inward combined and (b) combined with a direct upward force. The directional forces applied to the shoulder complexes needs to be backward-outward on the arm and backward-upward to the shoulder blade, and a straightening of the spinal curve in the upper back.
Ideally, the support for each functional unit should be coupled to provide a counterbalance to the forces being exerted on the body. This means that the right pelvic bones and the left shoulder should be coupled together and the left pelvic bone and the right shoulder complex should be coupled together. By coupling the opposite functional units together, a greater amount of stabilization is provided when the body is at its greatest moment of strain, just after the heel of the leading foot strikes the ground and the body's weight begins to project over the foot.